1968 40 hp ski twin carb adjustments

[samboatman]

Where do I start to adjust the carb from scratch. I'll use a pail to get it kinda close, I'm almost ready to fire it up. I originally removed carb, cause the choke coil showed open....fried. I cleaned the carb out, it was ok. I also blew through where ever I could....LOW PRESSURE. Also looking for tips on final adjustments, considering the Detroit river is pretty chlli right now. Heres a pic of my carb

 

[1946Zephyr]

Re: 1968 40 hp ski twin carb adjustments

Low Speed = 1 1/2 turns (top)
High Speed = 3/4 turn (bottom)

I'm surprised that carb doesn't have a fixed orifice on the high speed

 

[tashasdaddy]

Re: 1968 40 hp ski twin carb adjustments

good info here, carb cleaning, ethanol poisioning, carb adjustments
http://forums.iboats.com/showthread.php?t=299680

 

[lindy46]

Re: 1968 40 hp ski twin carb adjustments

Low Speed = 1 1/2 turns (top)
High Speed = 3/4 turn (bottom)

I'm surprised that carb doesn't have a fixed orifice on the high speed

Looks like an older carb.

 

[F_R]

Re: 1968 40 hp ski twin carb adjustments

Looks like an older carb.

No, we have an identification problem here. A 1968 Ski Twin is 33hp, not 40. It was sold as a low price alternative to the more deluxe 40. Even though it actually cost more to make the adjustable jet, they did it so it wouldn't have all the bells and whistles of the 40. Otherwise, who would buy the 40?

Interestinly, in the 1970's the 40hp reverted back to the 33hp design. More accurately, it was the Gale 40 of the 1960's with some improvements.

 

[1946Zephyr]

Re: 1968 40 hp ski twin carb adjustments

Yea, I like the later 40 compared to the big heavy Super Quiet design. It's more or less based on the 28's and 33's

 

[lindy46]

Re: 1968 40 hp ski twin carb adjustments

No, we have an identification problem here. A 1968 Ski Twin is 33hp, not 40.

Thought that carb looked like the ones used on '58 and '59 35hp models.

 

[1946Zephyr]

Re: 1968 40 hp ski twin carb adjustments

What is the model number on that motor. That does look like the carb that my 59 Johnson 35 had, now that you mentioned it lindy46.

I guess there were big twin type motors that went back to the dual needle set up, but I understand that happened in 1971 on the 40hp (Type II) The earlier 40's I believe 63 and older were a dual needle set up. 1964 - 70 40's had the fixed orifice on the high speed (Type II) and there was no adjustment needle.

 

[F_R]

Re: 1968 40 hp ski twin carb adjustments

What is the model number on that motor. That does look like the carb that my 59 Johnson 35 had, now that you mentioned it lindy46.

I guess there were big twin type motors that went back to the dual needle set up, but I understand that happened in 1971 on the 40hp (Type II) The earlier 40's I believe 63 and older were a dual needle set up. 1964 - 70 40's had the fixed orifice on the high speed (Type II) and there was no adjustment needle.

They all date back to the days of the 1955 -ish 25hp. Different bore sizes, different linkages, different chokes. The 33hp motor we are discussing here did have the same electric choke as the '59 35hp, thus the same float bowl, thus the same needle jet. All in the same family.

 

[circle hook]

Re: 1968 40 hp ski twin carb adjustments

that carb looks like the sister to my carb, A 1971 40HP it has the same 2, low and high speed needles, and my carb also has the choke solenoid on the bottom like yours.

 

[1946Zephyr]

Re: 1968 40 hp ski twin carb adjustments

Yea, I think the 28's were built from left over parts from the 30 hp's and the 33's were built from left over parts of the 57 35's. Only differences are the cowling. I don't think those have thermostats either, unlike the 40's.